Liquid fuel pump for internal combustion engines



Novl 10, 1931. J. BENES I 1,831,699

LIQUID FUEL PUMP FOR INTERYJAL COMBUSTION mamas Filed NOV- 5, 1930Patented Nov. 10, 1931 PATENT OFFICE JOSE]? ms, 02 VSETIN,CZECHOSLOVAKIA LIQUH) FUEL rm FOB INTERNAL COMBUSTION ENGINESApplication fled November 3, 1930, Serial No.

This invention relates to an improved liquid fuel pum for internalcombustion engines designe to deliver variable quantities of fuel to thereservoir connected with the injecting nozzle, use being made therein ofa well-known constructionof piston which is provided with a radial holeor holes and with an axial or longitudinal hole, the latter being incommunication with the said radial holes and with the working space ofthe pump and the radial holes being -dapted during the movement of thepiston to be placed in communication with the suction chamber of thepump.

The object of the resent invention is to provide an improv constructionof fuel pump capable of being readily and accuratel adj ust'ed to supplyvariable quantities of fn in which the grinding in and polishing out aregreatly simplified.

It has previously been proposed, in a fuel pump provided with a pistonof the character above referred to, to mount a slidable sleeve or arotary sleeve rovided at one or both of its ends with V- aiped aperturesor inclined faces, on the'sai piston for the purpose of varying the timedurin which the radial holes in the piston are opt in communication withthe suction chamber of the map.

e invention consists in a liquid fuel pum for internal combustion engmesprovided with a iston of the character referred to, in which e cylinderwherein the piston moves comprises two stationary parts, the

end of one of which abuts against the end of the other part and is cutalong two or more inclined or helical surfaces to produce a free spaceof variable height with respect to the radial holes in the piston andthe piston being adapted to be adjusted in the circumferential directionof the two 0 linders.

While the period 0 injection is controlled b the inclined or helicalsurfaces formed at t e end of one of the stationary parts of thecylinder in co-operation with the radial holes provided at a certaindistance from the end of the piston facing the working chamber of thepump, the starting ofthe in ection is controhed b the said end ofthepiston in co- 493,210, and in arm Britain May 21,1930.

operation with radial holes provided in the part of the cylinderconstituting the working chamber. V

The invention also consists in the improved construction of liquid fuelpump substantial- 5;

1y as hereinafter described with reference to the accon'ipanyingdrawings, in which Figure 1 is a sectional elevation of the improvedfuel pump, whilst Figure 2 is a diagram illustrating the adjustment ofthe period of injection by means of the inclined surfaces formed at theend of one part of the cylinder.

Referring to the drawings, a is the easing or frame of the pump, b is acylinder fixed in the casing a and c is another cylinder in axialalignment with the fixed cylinder 1) and secured thereto. d is thepiston which is provided with radial holes 6 and with an axial orlongitudinal hole f, the m to be placed in communication with the suc-75 tion chamber h of the pump. z' are radial holes provided in the fixedcylinder 6, through which communication is effected between the suctionchamber h and the working space 9, which communicates through 0 anon-return valve 8 with the chamber-from which the fuel is delivered tothe injection nozzle. i are longitudinal holes provided in the cylinder6 through which the suction chamber k can additionally communicate withthe working space {through a space left free between the cylinder 0 andthe cylinder b and through the radial and longitudinal holes provided inthe piston.

The cylinder 0 abuts with its end against the cylinder b and is cut, asis diagrammaticall'y indicated in Figure 2, which is a developement ofthe peripheral surface of the cylinder 0 and shows the position of theradial holes 0 in the piston relatively to the inclined cut surfaces 9and 9 at the end of the cylinder 0. The piston cl is adapted to berotated by a rack and pinion n, 0 respectively, the latter beingarranged to engage with the piston d by means of longitudinal slots 0provided in the pinion and a transverse pin (2 mounted in the piston d.As the piston d is rotated relatively to the cylinder 0 the moment atwhich'the radial holes 6 will be uncovered'will be varied and retardedover a distance 6 or over a distance 0 according as to whether the holese are in the position indicated by 1 or 2 relatively to the inclinedsurfaces at the end of the cylinder c, it being of course understoodthat the adjustment can be eflected over the whole of the distancebetween 0 and 2.

A space 7- is left between the cylinder 0 and the casing of the pump,which space is in communication with the suction chamber is sucked infrom the suction chamber h and passed through the longitudinal hole finto the working chamber g. This suction takes place until the radialholes e in the piston are completely covered by the inclined surfaces q,9 cut in the upper end of the cylinder 0. The further movement of thepiston in a downward direction causes the radial holes 2' in thecylinder 12 to be uncovered, whereby further fuel is sucked in from thesuction chamber. After the piston has reached the beginning of theworking stroke and starts moving in an upward direction, the pistongradually covers the radial holes i in the cylinder b and when the saidholes are completely covered, the fuel is forced by the piston from theworking chamber 9 and past the non-return valve 8 into a chamber fromwhich the fuel is delivered to the injection nozzle. The injectioncontinues until the upper edge of the radial holes e provided in thepiston reaches the inclined surfaces 9, Q1 cut in the end of thecylinder 0 and the said radial holes are thereby uncovered. The fuel isthereupon pressed from the working space 9 of the pump into the suctionchamber h and the nonreturn valve closes the communication between theworking space and the delivery chamber which communicates with theinjecting nozzle. It will thus be seen that the period of injection iscontrolled by the setting of the radial holes 6 in the piston relativelyto the cut surfaces g, g; in the upper end of the cylinder 0. As thepiston continues its upward movement, fuel is forced from the workingspace into the suction chamber throu h the radial and longitudinal holesin the piston and also through the radial holes 2' provided in thecylinder 6, until the latter holes are closed by the upper part of thepiston whereupon the fuel opens the nonreturn valve and is forced intothe delivery chamber. This operation is continued until the pistonreaches the end of its working stroke, whereu on the operation isrepeated as above descri ed.

I wish it to be understood that the details of construction may bemodified withoutin any way departing from the spirit of the invention.

What I claim is 1. A liquid fuel pump for internal combustion engineshaving a stationary cylinder comprising the working chamber of the pump,another stationary cylinder the end of which abuts against the end ofthe other cylinder, the end of one of these two cylinders abuttingagainst the other one having inclined surfaces, a piston capable 'ofreciprocating within the said two cylinders and having a longitudinalhole in communication with the working chamber of the fuel ump andradial holes in communication witthe said longitudinal hole and meansfor adjusting the said piston in the circumferential direction of thetwo cylinders in order to adjust the position of the radial holes in thepiston relatively to the inclined surfaces provided at the end of one ofthe cylinders, the space left free between the said inclined surfacesand the end of the other cylinder being in communication with thesuction chamber of the fuel pump, as and for the purpose set forth.

2. A liquid fuel pump for internal combustion engines as claimed inclaim 1 and in which the cylinder comprising the working chamber hasradial holes between the working chamber and the suction chamber of thepump arranged in such .a position as to enable the starting of the inection to be controlled by the end of the piston, as set forth.

In testimony whereof I have signed my name to this specification.

JOSEF BENES.

